Police arrested 35 people suspected of attempting to overthrow the government, said an Ethiopian government spokesman.
Government spokesman Ermias Legesse said the group was arrested Friday with weapons, communication equipment, military uniforms and written plans. He said it called itself the "May 15" group after controversial 2005 elections held on that date.
Ermias said Saturday the group was established by former opposition leader Berhanu Nega. Berhanu was elected mayor of Addis Ababa in 2005, but arrested afterward with more than 100 other opposition politicians and tried for treason. He and the others were freed by a pardon in 2007.
He's now assistant professor of economics at Bucknell University in Lewisberg, Pa., the university's Web site said.